Generally, the current used UV sterilization system is provided with autocleaning structure to clean the surface of UV lamp protective sleeve. The conventional way of cleaning comprises mechanical cleaning and mechanical plus chemical medicament cleaning. In mechanical cleaning, the dirt is removed by driving wiping means along the surface of the lamp protective sleeve back and forth, thus mechanical cleaning can be realized with a simple structure and does not need addition of chemical medicament. However, a lot of heat will be generated during the lighting of the UV lamp and thus solid dirt tends to be formed on the surface of the protective sleeve while performing fluid sterilization. It is difficult for the mechanical cleaning structure to remove the solid dirt and there is a need to add some chemical medicament.
The mechanical plus chemical medicament cleaning structure in the prior art, e.g. disclosed in Chinese patent application 00811520.6, comprises a cleaning sleeve slidably engaging the outside of the UV lamp protective sleeve, and a cleaning room within the cleaning sleeve which is contacted with part of the outside of the UV lamp protective sleeve and filled with cleaning liquid, said cleaning room comprises an opening leading to the outside of the cleaning sleeve, and a pressure balance member is provided in the opening for the sealing between the opening and the outside of the cleaning sleeve. The pressure balance member is movable with the change of pressure gradient therein and move a driving device for the cleaning sleeve along the outside of the UV lamp protective sleeve. The cleaning system of this kind can efficiently clean the surface of the lamp protective sleeve by adding chemical medicament, but it is difficult to manufacture for its complicated structure, and meanwhile each cleaning room is independently connected with an addition means for cleaning liquid, which as well renders the system complicated. Therefore, it is desirable to develop a simple cleaning structure for the lamp protective sleeve of the UV sterilization system in which chemical medicament can be added for efficient cleaning, such that the cost is reduced.